PGP generated by the sequential action of MMPs (e.g., MMP9) and PE-mediated degradation of collagen (13, 15) can activate CXCR2 on a variety of cell types (16), and it has been described as a mediator of endothelial dysfunction owing to increased endothelial permeability (18) and endothelin-1 (ET-1) production (17). This evidence concerns the gene EDN1 and endothelial dysfunction.